WO1999020850A1

WO1999020850A1 - Valve-actuator for use with a lavatory-flush cistern water-inlet valve

Info

Publication number: WO1999020850A1
Application number: PCT/GB1998/003094
Authority: WO
Inventors: John Alan Jackson
Original assignee: John Alan Jackson
Priority date: 1997-10-18
Filing date: 1998-10-16
Publication date: 1999-04-29
Also published as: AU9547898A; GB9820486D0

Abstract

A valve-actuator for use in conjunction with a lavatory-flush cistern to enable and control its refilling via a cistern water-inlet valve from a water-supply, comprises: a main float-chamber (12) able to communicate freely with the cistern (1) at or closely adjacent to and below the desired maximum water-level (C) therein and which therefore is over-topped and floods when the cistern fills to that level, a float (13) within that main float-chamber and movable therein downwards under gravity from an uppermost position to a lower position, and vice versa upwards under its buoyancy, said uppermost position being one at which the float remains at least partly and preferably fully submerged beneath its natural buoyancy level when the float-chamber is flooded, an attachment point (15) associated with the float (13) for operating means responsive to its position within said main float-chamber which operating means are adapted either directly or indirectly to close the cistern water-inlet valve (2) when the float (13) is in its uppermost position and conversely to open said cistern water-inlet valve (2) when the float (13) is in a lower position, and a main float-chamber drainage outlet (16a, 16b) through which, when the water-level in the cistern falls as the lavatory is flushed, the water within said float-chamber (13) is discharged at a controlled rate such that the float does not de-submerge and then fall from its uppermost position, thereby opening the water-inlet valve (2) and commencing to refill the cistern, until flushing has effectively-emptied the cistern, thus obviating water-wastage. Preferred features check and control slow leaks and/or fast leaks from the cistern (1), and/or monitor/indicate such leakages.

Description

VALVE-ACTUATOR FOR USE WITH A LAVATORY-FLUSH CISTERN WATER-INLET VALVE

This invention relates to a valve-actuator for use in conjunction with a lavatory-flush cistern water-inlet valve, and of course to flushing-cisterns equipped therewith.

For well over a century there have been systems for flushing lavatory pans with water. They function by swiftly 'dumping' the water within a cistern into the lavatory pan, so as to flush it clean.

The swift dumping of a cistern-full of water into the lavatory pan (usually under control of the user, but sometimes automatically at intervals) is normally achieved in one of two ways, either by inducing the water to syphon-drain out of the cistern, or by opening an outlet-valve in the base of the cistern and allowing the water to gravity-drain out - in both cases via a wide-aperture bore, which enables the entire contents of the cistern to escape in a matter of 5-10 seconds. The syphon-drain system is at present almost universally used in Britain, since it more surely complies with the most stringent requirements for preventing any possibility of leakage, provided that the high water level in the cistern is not above the invert level of the cistern syphon - but the gravity-drain system has some advantages, particularly because it provides a more efficient flush due to less energy loss, so it is used in many other countries, and in the interests of international standardisation it is thought likely to become permissible and widespread even in Britain before long.

Be that as it may, in all such systems after the water within the cistern has been 'dumped' via a syphonic or other outlet into the lavatory pan the outlet will then in some manner be effectively closed so that the cistern can be re-filled with water from the mains or other supply in order to make the system ready for re-use. The re-filling of the cistern is traditionally effected via a float-actuated water-inlet valve arrangement which is responsive to any fall in water-level within the cistern (as its contents are dumped into the lavatory pan) below its full-point to admit water from the mains or other supply.

It is the re-filling of the cistern with which the present invention is concerned, because the traditional manner in which this is achieved leaves much to be desired.

For a very long time, probably from the very inception of water closets, the emptied cistern has been refilled from the water-supply via an inlet valve directly responsive to the water-level within the cistern or, more strictly, responsive to the vertical movements of a float within the cistern, which float is forced by its buoyancy to rise upwards as the water-level in the cistern rises during filling of the cistern, but falls downwards under gravity as the water-level falls when the cistern is emptied.

The float-actuated inlet-valve through which water enters the cistern from the water-supply is fully-closed when the float rises to the cistern-full level, and is opened when the float falls from its high water-level towards the bottom of the emptied cistern, but in the simplest and most conventional arrangements the inlet-valve is partly-open and partly-shut when the float is at any level intermediate these extremes. Moreover, with inlet-valves of the now-prevalent equilibrium type the valve opens fully almost immediately the float begins to drop.

Consequently when the lavatory pan is flushed the water-level within the cistern falls quickly, and whichever type of inlet-valve is employed it immediately starts to open, and in the case of an equilibrium valve it opens fully, so that water is admitted therethrough before the cistern has emptied, and thus before the cistern-outlet has shut off, so that more water is discharged from the cistern at each flush than the cistern itself originally contained. This is unnecessary and therefore wasteful of water. Conversely, when the cistern-outlet has shut off and the cistern begins to refill it does so at best much more slowly than it emptied, and in the case of the conventional water-inlet valve the speed of refill is further diminished by the fact that as the water-level in the cistern rises the inlet valve closes more and more.

Both these things are therefore the exact opposite of what one should want, which is that on emptying the cistern the inlet valve should stay fully closed until after the cistern has been emptied and the outlet valve has closed, whereas on filling the cistern the inlet valve should stay fully open until the last moment, when the cistern is once more full, and only then should it close.

Searching the prior art with hindsight, it can be seen that there have been various proposals designed to overcome deficiencies in the traditional arrangement. Seemingly the most pertinent to the present invention from both aspects is perhaps UK Patent Application GB 2,102,856 A, where the float is supported by its natural buoyancy within an auxiliary float-chamber in the form of an open-topped container fixedly-mounted within the main cistern, which float-chamber will be flooded when the rising water level in the main cistern over-tops the walls of the float-chamber.

And the same UK Patent Application GB 2,102,856 recognised the desirability of delaying the opening of the inlet-valve until after the cistern has emptied and its outlet valve has closed and envisaged the provision of communication between the main body of the cistern and the auxiliary chamber taking place via a syphonic tube with the result that the inlet valve remains closed until there is sufficient discharge from the auxiliary float- chamber through the syphonic tube, and as the latter is slow compared with the emptying of the cistern, the inflow of inlet water during the period that the cistern-outlet is open is to some extent reduced.

But although this arrangement does of course work its success in delaying the opening of the inlet-valve is at best rather limited, and anyway is gained at the cost of re-introducing problems stemming from the rising water- level when refilling the cistern. In order to restrict the rate at which water in the float-chamber drains out through the syphonic tube that must be of narrow diameter, and when the cistern starts to refill capillary action due to water retained in the narrow syphonic tube tends to back-fill the float- chamber from the bottom before the rising water level in the main cistern over-tops the walls of the float-chamber and floods it from the top. With the conventional type of water-inlet-valve this will at best delay refilling of the cistern, and worse still with a valve of the equilibrium type it can prematurely close the valve and thus prevent the cistern from refilling to the proper level - which is not only bad in itself but also eliminates any possibility of delay in opening of the inlet-valve on the next subsequent flush because the valve will then open as soon as the water-level drops. It is no doubt for these reasons that the construction proposed in UK Patent Application GB 2,102,856 A has certainly never been adopted widely, or perhaps at all.

Be that as it may, it is the most basic aim of this invention to provide a valve-actuator arrangement which succeeds on both counts, that is to say which achieves the water-saving advantages of delayed opening of the inlet- valve on flushing the cistern and yet prevents premature closing of the inlet- valve during refilling of the cistern.

According to one aspect of the present invention there is provided a valve-actuator, for use in conjunction with a lavatory-flush cistern water-inlet valve from a water-supply, which valve-actuator comprises:

- a main float-chamber able to communicate freely with the cistern at or closely adjacent and below the desired maximum water-level therein and which therefore floods when the cistern fills to that level;

- a float within said main float-chamber and movable therein downwards under gravity from an uppermost position to a lower position, and vice versa upwards under its buoyancy, said uppermost position being one at which the float remains at least partly submerged beneath its natural buoyancy level when the float-chamber is flooded;

- an attachment point associated with the float for operating means responsive to its position within said main float-chamber which are adapted either directly or indirectly to close the cistern water-inlet valve when the float is in its uppermost position and conversely to open said cistern water-inlet valve when the float is in a lower position; and

- a main float-chamber drainage outlet through which, when the water- level in the cistern falls as the lavatory is flushed, the water within said float- chamber is discharged at a controlled rate such that the float does not de-submerge and then fall from its uppermost position, thereby opening the water-inlet valve and commencing to refill the cistern, until flushing has effectively-emptied the cistern, thus obviating water-wastage.

The uppermost position of the float within the main float-chamber should be below its natural buoyancy level when said float-chamber is flooded, so that the operating means then exert a positive closing force upon the cistern water-inlet valve and do not cease to do so until the water-level within the main float-chamber has fallen to the natural buoyancy level of the float after which the float will begin to descend and allow the water-inlet- valve to open, but only after the flush has completed. The uppermost position of the float will preferably be one at which it is fully submerged when the float-chamber is flooded; and it should also be understood that the valve- actuator now provided is best adapted for use in conjunction with a water- inlet-valve of the equilibrium type.

While other arrangements could be envisaged, it is much the most convenient when the main float-chamber is an open-topped cup arranged for location within the cistern so that the lip of that cup substantially coincides with the desired maximum water-level within the cistern.

The operating means will advantageously comprise one or more linkage(s) secured to the attachment point on the float and which are operative while the latter is at its uppermost point to close a cistern water- inlet valve from a mains water-supply. This water-inlet valve will desirably be one of the kind which does not operate against the inlet pressure of the mains supply, i.e. an equilibrium-type valve as already envisaged above. The drainage outlet at its simplest may be an aperture in or closely- adjacent to the base of the main float-chamber. It is however desirable (if only because this arrangement favours other preferred features of the invention, as will become clear later) that the drainage-outlet should be a syphonic-tube with its inflow end connected to the main float-chamber at or closely adjacent to the base thereof and below the lowermost point of the float therein, said tube having its apex at or closely adjacent the level of communication between said float-chamber and the cistern, its invert point just below that level, and its outflow end disposed below its inflow end sufficiently to allow the syphon to operate on flushing.

It is necessary to flood the syphon system on re-filling in order to evacuate most of the air in the syphon to ensure that the syphon works on flushing. Therefore the invert level of the syphon should be just below the high water level. Consequently some water will enter the float-chamber via the syphon tube on re-filling of the cistern. This however will be only a small amount which will not affect the float valve before the rising water level overtops the float-chamber lip.

Provided that the components are correctly dimensioned the above- described arrangement will achieve the basic aims of this invention without further elaboration. All the same, it is a very desirable further feature of this invention to provide a water-inflow restrictor associated with said drainage- outlet which is adapted, as the water-level in the cistern rises on refilling same, to restrict or prevent refilling of the main float-chamber by back-flow via said drainage outlet, to such an extent that said float-chamber is sufficiently filled to move the float to its uppermost, closed position, and thus close the cistern water-inlet valve, only when the water in the cistern reaches its desired maximum level and thereby over-tops and floods the main float- chamber.

The water-inflow restrictor for the main float-chamber at its simplest can be any kind of restriction orifice or one-way, non-return valve, e.g. a flattened tube formed of flexible material, such as rubber or plastics. When however the drainage-outlet is, as preferred and explained above, in the nature of a syphonic tube then the water-inflow restrictor can very conveniently and advantageously take the form of a non-capillary chamber interposed in the syphonic tube between its apical invert point and its outlet end, i.e. that end which communicates with the cistern.

Due to the fact that the non-capillary chamber is in the inlet path of the syphon when the cistern is filling it will prevent any back-syphoning into the float-chamber until the invert level of the syphon is reached.

The valve-actuator as broadly disclosed above and to be described in more detail hereinafter will achieve the basic objectives of this invention, that is to say it will minimise and at best avoid any wastage due to water entering the cistern from the inlet-valve before the outlet valve has closed, and it will also thereafter ensure that the cistern refills at the fastest possible rate until the last moment when the inlet-valve shuts off as the water-level in the cistern reaches its desired maximum level.

These however are not the only desiderata in lavatory-flushing systems, which like everything are sometimes liable to malfunction, and in particular can suffer from leakage. There are various ways in which such leakage may occur, some of which afflict all types of flushing systems, but systems of the bottom-valved, gravity-drain kind are particularly prone to leakage past the flushing-outlet valve.

There are indeed two kinds of such leakage, which can be broadly categorised on the one hand as slow-leaks, e.g. due to failure of the cistern- outlet valve to seat properly, and on the other hand as fast-leaks, e.g. due to the cistern-outlet valve jamming wide open.

The nature of a leak, either slow or fast, is intuitively obvious, but can if necessary be defined as follows. A slow-leak, due usually to the failure of the flushing outlet valve to re-seat property after the cistern has emptied, is one which does not prevent the cistern from refilling until the water-inlet valve closes, but thereafter causes the water level in the cistern slowly to drop until the inlet-valve opens again, and so on cyclically. A fast-leak on the other hand, due usually to the flushing outlet valve somehow jamming wide open, is one which actually prevents the cistern from refilling.

Perhaps paradoxically, it seems to be the case that slow-leaks are the more undesirable, since they can go undetected for long periods of time over which the amount of water thus wasted can become cumulatively very considerable, whereas fast-leaks are usually very self-evident so that steps are promptly taken to cure them. However both these kinds of leakage are undesirable and wasteful of water, so it is a further feature of this invention to provide means for checking at least slow-leaks and preferably also fast- leaks.

According to an especially preferred further feature of this invention the valve-actuator as already broadly disclosed herein (and which will be further described and illustrated subsequently) is additionally provided with means responsive to a slow-leak from the cistern to disable the discharge of water from the main float-chamber thus preventing opening of the water-inlet valve.

Such disabling means may be of an essentially mechanical nature, thus for instance can advantageously comprise:

- an auxiliary float-chamber, able to communicate freely with the cistern at a level closely adjacent to but just below its desired maximum water-level;

- an auxiliary float within said auxiliary float-chamber and movable therein under gravity between an upper enabling position and a lower disabling position, and vice versa under buoyancy, the auxiliary float when as normal the auxiliary float-chamber is full being submerged below its natural buoyancy level and therefore positively urged towards its upper enabling position but when the auxiliary chamber is emptied urged by gravity towards its lower, disabling position; - an aperture in and substantially at the apex of the syphonic tube through which water is discharged from the main float-chamber, and a valve member which normally seals said aperture;

- one or more mechanical interconnection(s) between the valve member and the auxiliary float so arranged that when the auxiliary float falls under gravity to its lower, disabling position the valve member is caused to unseal the aperture, thus breaking the syphonic path and disabling further discharge of water from the main float-chamber, thereby preventing the float descending to its lower valve-opening position; and

- a water-outlet from the auxiliary float-chamber so dimensioned and located that water escapes therefrom into the cistern so slowly that on flushing the cistern the syphonic-tube will drain the main float-chamber and allow the inlet valve to open before the auxiliary float falls to its lower, disabling position.

In a simple and convenient arrangement the mechanical interconnection(s) can comprise an arm pivotal ly-mounted intermediate its ends and connected at one end to the auxiliary float and at its other end provided with a sealing pad which normally bears down upon the aperture in the apex of the syphonic tube.

On the whole however, in order to obviate the possibility of mechanical failure or malfunction in the arrangement just described, it is generally preferred instead to employ disabling means of an entirely hydraulic, non-mechanical nature, which thus can very desirably comprise:

- an auxiliary chamber, able to communicate freely with the cistern at a level adjacent to but below its desired maximum water-level; and

- a second syphonic tube running from a point at or closely adjacent to the bottom of said auxiliary chamber to join the first syphonic tube at or closely adjacent its apex, so that whenever the said auxiliary chamber becomes empty air will enter the syphonic system via the second syphonic tube to disable the discharge of water from the main float-chamber via the first syphonic tube;

- said second syphonic tube being however so dimensioned relative to the first syphonic tube that water escapes from the auxiliary chamber via the syphonic system so slowly that on normal flushing of the cistern the first syphonic tube will drain the main float-chamber and allow air to enter the syphon via the first syphonic tube before the second syphonic tube can drain the auxiliary chamber.

While it is regarded as generally most important to check slow-leaks in the manner already broadly described above, it is also of course very desirable to check any fast-leaks that can develop, as for instance when the flushing system cistern-outlet valve jams open and the cistern cannot refill yet the water-inlet valve is still admitting water to the cistern from the mains supply.

According to yet another preferred feature of this invention there is therefore provided a valve-actuator, as herein described, which includes means responsive to a fast-leak from the cistern to over-ride the normal water-inlet valve control mechanism and bring about closure thereof even though the main float-chamber aforesaid has not been overtopped and flooded.

The over-ride means can advantageously comprise an auxiliary float- chamber, an auxiliary float within said auxiliary float-chamber movable between an upper inoperative position and a lower operative position, a pivotally-mounted lever one end of which is movable responsive to movement of the auxiliary float within the auxiliary float-chamber, the other end of said pivotally-mounted lever being normally disengaged from the main float and associated valve-operative linkage(s) but engageable therewith as the auxiliary float approaches its operative position, which lever when thus engaged lifts said linkage(s) towards and into the water-inlet valve-closing position as said auxiliary float falls to its fully-operative position, as well as one or more slow-drain outlets from said auxiliary float-chamber so dimensioned that when there is no fast-leak from the cistern which therefore refills at a desired rate the auxiliary float-chamber will flood, thus restoring the lever to its inoperative position, before the auxiliary float has fallen to its operative position.

With the preferred arrangement in which the float-chamber drainage- outlet is a syphonic-tube, the pivotally-mounted arm provided with the sealing pad to disable a slow-leak can advantageously serve also as the lever engagable with the main float and its associated linkage(s) to shut off the water-inlet valve in the case of a fast-leak.

Alternatively, the over-ride means responsive to a fast-leak can desirably comprise an open-pored porous slow-release sponge-type material disposed within the main float-chamber above the uppermost position of the main-float therein, from which sponge-type material, when the water-level in said float-chamber has fallen to open the cistern water-inlet valve, water will be released so as once more to raise the water-level in said float-chamber and thereby re-close the cistern water-inlet valve, but only after a period outside the normal filling time of the cistern.

This invention extends also to lavatory-flush cisterns of whatever type, when equipped with a water-inlet valve-actuator as herein disclosed, but it is believed to be especially effective and valuable when used in conjunction with those in which the flush-mechanism is of the bottom-opening, gravity- drain type and (as already indicated) those in which the water-inlet valve is of the equilibrium type.

At this point it is convenient to observe that the valve-actuator mechanism last described above will have fulfilled its own proper function when, in response to a fast-leak, it shuts off the water-inlet valve even though the main float-chamber is empty. That however is to cure one problem but to create another, because when the fast-leak has been cured the whole mechanism will need to be re-set. A convenient and indeed elegant re-setting arrangement has been devised for use in conjunction with the flushing-mechanism of the bottom-opening gravity-drain type which will now be described below.

According to a still further preferred feature of this invention there is provided a flush-mechanism of the bottom-opening gravity-drain type, for use in a lavatory-flush cistern, which flush-mechanism comprises:

- a buoyant plug, for seating in the bottom-opening of a gravity-drain lavatory-flush cistern to retain the water therein and normally held in situ on its seating by the pressure of the water in the cistern;

- a plunger attached at its lower end to said buoyant plug, and extending upwardly beyond the top of the cistern whereby the plug can be lifted to flush the cistern;

- said plunger comprising separate upper and lower sections detachably inter-engagable with each other by means of a catch mechanism;

- said catch mechanism comprising a catch member associated with one of said plunger sections which can be either engaged with or disengaged from an abutment associated with the other section;

- the engagement/disengagement of the catch member with the abutment being controlled by a float member responsive to the presence or absence of water within the cistern, so that when the water-level in the cistern is above a predetermined point the catch member engages with the abutment but disengages therefrom when the water-level falls below that point; and

- means operable by lifting the upper section of the plunger, when it is disengaged from the lower section thereof, to over-ride the valve-actuator mechanism when it has shut off the cistern water-inlet valve so as to re-set the system for normal operation.

The means for over-riding the water-inlet valve-actuator can advantageously comprise a displacement member which normally restricts the effective volume of the main float-chamber of said valve-actuator but which on lifting the upper section of said plunger when disengaged from its lower section is raised thereby increasing the effective volume of said float- chamber and therefore reducing the water-level therein thus opening the cistern water-inlet valve.

The preferred valve-actuator mechanisms as described above are able to achieve the further objectives of this invention, thus to prevent water wastage by closing the inlet valve in the event of a slow and/or fast-leak due to a leaking outlet valve in the base of a WC cistern. It is however a disadvantage of these arrangements that this also prevents the cistern from operating until it is repaired or manually overridden as previously described. It is however possible to provide an alternative arrangement which instead of shutting the whole system down uses the delayed-opening float-valve to indicate the presence of a leak, but in all other respects enables the cistern to remain fully functional.

The preferred embodiments of this invention as so far described above function well not only to save water from being wasted on normal flushing of the cistern but also to recognize and terminate water wastage caused by either slow - or fast-leaks from the cistern. However, in relation to such leaks they effectively terminate use of the lavatory pan until the cause of the leakage has been cured and/or the whole flushing system reset for normal operation. This in itself is admirable, but there can be circumstances in which it would be better to tolerate some water-wastage due to leakage (until the situation can be rectified) rather than shut-down the whole flushing system and thus render the lavatory-pan unusable. This may well be the case for instance in non-domestic environments such as public buildings, where it is probably important to keep all toilet facilities fully operational during the hours of public access and therefore high usage, but easy to effect repairs "after-hours" when the building is closed to the public. And it may be most especially important in e.g. hospitals, where the results of a non-operational lavatory are not merely offensive but can pose a serious health hazard which is particularly unacceptable in such an environment.

It is therefore another, partly-different objective of this invention (while adhering to its most basic aim of avoiding water-wastage during normal flushing) rather than using the delayed-opening float-valve actuator mechanism to terminate either slow- or fast-leaks instead to use the delayed- opening float-valve in such a way as to indicate the existence of a leak but in all other respects to leave the cistern fully operational.

At this point it is convenient to explain that if a conventional bottom- opening, gravity-drain cistern-outlet-valve has a slow-leak, water is added by the float-operated water-inlet valve to keep the water more or less at the high water level. When however a delayed-opening float-valve in accordance with this invention is installed in place of a conventional water-inlet valve, a leaking cistern-outlet valve will lower the water level to the delayed-action float-valve opening level before water can be added. This is because as the cistern water level drops due to the leak, the water level in the cup containing the float will closely follow the water level in the cistern due to the syphon connecting these two water levels. Water will then be added which will close the inlet valve at a level slightly higher than the valve-opening level, but still below the normal high-water level. And so on! Therefore, as the leak continues the float valve will keep opening and closing, thus maintaining the water level in the cistern between these limits. However, the valve-opening and valve-closing levels are close together, and for the purposes of this invention they can be regarded as a single valve-open/close level.

And the establishment of the cistern water level at this valve- open/close level can therefore be used to indicate that the cistern-outlet valve is leaking, without otherwise affecting the normal operation of the cistern.

According to an alternative aspect of this invention there is provided a leak-alert device comprising, in combination, a delayed-opening cistern water-inlet valve as herein disclosed, especially for use in conjunction with a bottom-opening, gravity-drain cistern, with a sensor/signal device able to sense the establishment of a valve-open/close water-level within the cistern and then, responsive thereto, to signal the existence of a slow-leak from the cistern water-outlet valve.

At its simplest the sensor/signal function can be discharged by a single device, e.g. a visually-perceptible water-level gauge, with or even without a float therein, and this may well be adequate (and no doubt most economic) in a domestic environment. However it is currently preferred (because the arrangement is envisaged as particularly suitable for use in public buildings, hospitals and the like, which have many, separate toilet facilities) to employ more sophisticated sensor/signal devices, able to sense the establishment of the valve-open/close water-level in situ within the individual cistern, but to transmit a signal indicative of that state to a remote indicator.

Looking at the matter overall, it will be seen that this invention improves upon pre-existing arrangements in several different ways. It provides separate devices to deal with fast and slow-leaks as described, which can be used either in combination or separately, so that a valve can be equipped with either a fast-leak device or a slow-leak device or both. Although both functions will usually be desirable, in areas where the water supply is intermittent and is liable to be cut off for long periods, it may be practical to omit the fast-leak device. Other advantages will become apparent below.

In order that this invention may be still better understood various embodiments thereof will now be further described, through by way of illustration only, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic, partially side-elevational and partially cross-sectional view of one very simple embodiment, designed to avoid water-wastage by delaying the opening of the cistern water-inlet valve until after the cistern-flushing outlet has closed but thereafter to maintain the water-inlet valve fully open until the cistern has been refilled to its desired maximum level;

Figure 2 is a view otherwise identical to Figure 1 of an improved embodiment which additionally includes a water-backflow restrictor;

Figure 3 is a still-diagrammatic, perspective view of a more realistic embodiment of the same construction as in Figure 2;

Figure 4 is a view similar to that of Figure 2 of an otherwise identical embodiment which however includes a modification which enables the delay imparted to the opening of the cistern water-inlet valve to be varied at will within certain limits;

Figure 5 is a still-diagrammatic, perspective view (similar to Figure 3) of a more realistic embodiment of the same construction as in Figure 4;

Figure 6 is a diagrammatic, partially side-elevational and partially cross-sectional view of an improved embodiment of the invention which not only attains the aims of the embodiment of Figures 2 and 3 but also is further elaborated by the inclusion of a mechanism to ensure that the cistern water- inlet valve is held closed despite any slow-leak which might develop if the cistern flush-valve closes but fails to seat properly;

Figure 7 is a view generally similar to Figure 6 of an alternative embodiment which achieves the same aim but by hydraulic rather than mechanical arrangements;

Figure 8 is a still-diagrammatic view, in other respects similar to that of Figure 7 but in which the auxiliary chamber is superimposed on the main float-chamber;

Figure 9 is a side-elevational view of both the main float-chamber and the superimposed auxiliary chamber of the embodiment of Figure 8, taken in the direction of arrow E there shown;

Figure 10 is an horizontal cross-sectional view taken on the line X-X in Figure 9; Figure 11 again is a diagrammatic, partially side-elevational and partially cross-sectional view of a still further embodiment of the invention, in other respects broadly similar to that of Figure 6 but which besides the mechanism for dealing with slow-leaks also now incorporates additional mechanical means whereby the cistern water-inlet valve can be shut off should the cistern flush-valve somehow jam open, and thereby give rise to a fast-leak;

Figure 12 is a still diagrammatic top-plan view of a more realistic embodiment of the arrangement of Figure 11 ;

Figure 13 is a diagrammatic, partially side-elevational and partially cross-sectional view of an embodiment otherwise identical to Figure 6 but which also incorporates one simple form of non-mechanical, essentially hydraulic means whereby the cistern water-inlet valve can be shut off should the cistern flush-valve somehow jam open, and thereby give rise to a fast- leak;

Figure 14 is a view, otherwise very similar to that of Figure 7, of another alternative and perhaps more reliable embodiment of an entirely hydraulic arrangement for shutting off the cistern water-inlet valve in case of a fast-leak;

Figure 15 is a diagrammatic, partially side-elevational and partially cross-sectional view of a water-cistern for a flushing lavatory pan, fitted with a bottom-opening, gravity-drain flushing system and equipped with a water- inlet valve-actuator arrangement as shown in Figures 8 to 10;

Figure 16 is a cross-sectional view, on an enlarged scale, of the supplementary valve-actuator resetting mechanism associated with the flushing-system plunger of Figure 15;

Figure 17 is a horizontal cross-sectional view taken on the line XVII- XVII in Figure 16; Figure 18 is near-realistic but still schematic, perspective view, essentially similar to Figure 3, which incorporates a cistern-leakage indicator device;

Figure 19 is a partly cut-away and cross-sectional view, on an enlarged scale, taken on a vertical plane through the adjacent parallel axes of the main-float-chamber of the valve-actuator and the cistern-leakage indicator device as shown in Figure 18;

Figure 20 is an horizontal cross-sectional view through the indicator component of the device shown in Figure 19;

Figure 21 is a vertical cross-section through the indicator component shown on Figure 20;

Figure 22 is a perspective view, similar to Figure 18, of an alternative embodiment of cistern-leakage indicator device;

Figure 23 is a partly cut-away and cross-sectional view, taken on a vertical plane through the adjacent, parallel axes of the main-float-chamber of the valve-actuator and the cistern-leakage indicator device shown in Figure 22;

Figure 24 is a diagrammatic partially side-elevational and partly cross- sectional view of a simple embodiment of valve-actuator otherwise similar to that of Figure 7 but modified so as to refill the cistern after the leak mechanism has prevented the inlet valve from opening due to a leaking outlet valve; and

Figure 25 is a diagrammatic, partially side-elevational and partly cross-sectional view of another simple embodiment of cistern, flush- mechanism and valve-actuator otherwise similar to that of Figure 15, but modified so as to refill the cistern after the leak mechanism has prevented the inlet valve from opening due to a leaking outlet valve.

It should be noted that in all the drawings the same reference numerals are so far as possible used to indicate the same (or basically similar) components, and if there are some drawings in which certain reference numerals do not appear they should be readily identifiable by referring to other drawings in which they do appear.

Referring first to Figure 1 , it will be seen that a lavatory-flush water cistern 1 is provided with a water-inlet valve generally indicated 2 through which the cistern is connected to (and refilled from) a mains water-supply 3. Here (as in all the embodiments) the inlet valve 2 is of the preferred equilibrium type which does not operate against the pressure of the mains supply, but instead uses the mains pressure to close the valve when a leakage path through the valve is blocked by means of an externally-applied sealing pad 4. This equilibrium-type valve construction is by now well- known, and need not be further described or illustrated. The sealing pad 4 is pressed onto the valve 2, to close the leakage aperture therein, by a stub- arm 5 mounted on a pivot 6 and rotated thereabout by a lever 7. When however lever 7 is moved downwards (into the position shown in dotted lines) the stub-arm 6 no longer presses the pad 4 onto the valve 2, so that the leakage path is opened, thus opening the valve 2 and permitting water from the mains-supply 3 to enter in the direction of arrow A and to exit from the valve 2 into the interior of the cistern 1 in the direction of arrow B.

The cistern 1 is of course also provided with an externally-operable water-flush mechanism, generally indicated 8, which however can be of any conventional construction and therefore needs no further description or illustration, except when modified in accordance with this invention as subsequently described (see Figure 16).

Within the cistern 1 there is provided a cup-shaped main float- chamber 10, with its lip 11 coincident with (and indeed substantially defining) the desired maximum water level C within the cistern 1 , but with its bottom 12 well above the minimum water-level D attained in the cistern 1 when it is effectively empty.

Moveable vertically within the main float-chamber 10 is a float 13, upstanding from which is a post 14 attached at pivot 15 to the end of lever 7 which controls operation of the water-inlet valve 2. It will be seen that when the float-chamber 10 is full of water (having been flooded by the rising water- level in cistern 1 , as it is refilled, reaching the maximum water-level C and overtopping lip 11 ) the float 13 is fully submerged and is urged by its buoyancy towards its uppermost position (shown in full lines in Figure 1) thus forcing lever 7 upwards and causing stub-arm 5 to close the aperture in the water-inlet valve 2 by means of sealing pad 4 and thus bring about closure of the inlet-valve to shut off the entry of water into the cistern 1 from the mains supply 3.

However, when water drains away sufficiently from cup 10 the float 13 falls under gravity to a lower position (shown in dotted lines in Figure 1) and thereby lowers the end of lever 7, so that it occupies the position also shown in dotted lines, and the sealing pad 4 on the stub-arm 5 then no longer closes the leakage aperture in the water-inlet valve 2, which therefore opens to admit water to the cistern 1 from the mains supply 3.

Closely adjacent the bottom 12 of the cup-shaped main float-chamber 10 is the inflow point of a first syphonic system comprising tube sections 16a and 16b, the outflow point of tube 16b being below the inflow-point of tube 16a so that when the cistern is flushed as the actual level of water begins to fall below its maximum level C (and thus the level of lip 11 ) water starts to syphon out of the main float-chamber 10 into the cistern 1 via syphonic tubes 16a, 16b.

The syphonic tubes 16a, 16b have narrow-diameter essentially- capilliary bores (or at least a section of reduced diameter in the syphonic path) such that drainage of the main float-chamber 10 therethrough is relatively slow, with the result that when operating normally the cistern 1 will have completely emptied and the flushing cistern-outlet will have re-closed before enough water has drained out of the float-chamber 10 to move the float 13 and associated linkages 14, 15, 7 and 5 into a position where the water-inlet valve 2 opens to admit water from the mains-supply 3. By thus delaying admission of mains water until after the flushing cistern-outlet has re-closed it is possible to prevent wastage of very considerable amounts of water, easily as much as say 10% of the water utilised per flush.

When the water-inlet valve 2 is opened, provided of course that the cistern-outlet has re-closed the actual water level within the cistern 1 will rise from level D back to level C, and will do so at the fastest possible rate so long as sufficient water does not enter the main float-chamber 10 until the actual water-level reaches its maximum level C, and then over-tops and floods the chamber 10, thereby returning the float 13 to its uppermost position and via linkages 14, 15, 7 and 5 pressing sealing pad 4 to close off the leakage aperture and thereby bring about closure of the water-inlet valve 2 and shut off admission of water to the cistern 1 from the mains supply 3.

It is however very desirable to guard against the re-entry of water into the main float-chamber 10 by back-flow through the syphonic tubes 16b, 16a. Referring now to the schematic embodiment of Figure 2, and/or the more realistic embodiment of Figure 3, it will be seen that they are provided with a chamber 17, interposed between syphonic tube sections 16a and 16b. In the absence of chamber 17 once the rising water level in cistern 1 reaches and surpasses the outflow point of tube-section 16b capillary action would otherwise induce back-flow from the cistern to the float-chamber - but this is precluded by the non-capilliary chamber 17 which prevents this from happening.

Only when the rising water level in the cistern 1 , reflected by a similar rise within the non-capillary chamber 17, finally reaches the invert point of the syphonic system will back-flow into the float-chamber commence. This will also purge most of the entrapped air from the system, and thus ensure operation of the syphonic system on the next flush. By the time that the rising water level in chamber 17 does reach the invert point of the syphonic system it is of no consequence, since the invert point is very closely adjacent to the desired maximum water-level C in the cistern, at which level the lip 11 of the main float-chamber 10 will anyway be over-topped and the float- chamber will be thereby flooded, shutting off the water-inlet.

Referring now to Figures 4 and 5, it will be immediately apparent that they are in other respects identical to the embodiments of Figures 2 and 3 (and the common features therefore will not be further described) but the upper end of the main float-chamber 10 is provided with an open-topped supplementary reservoir chamber generally indicated 20 which communicates with the main float-chamber 10 and indeed has a lip 21 at exactly the same level as lip 11 round the main chamber. The supplementary chamber 20 thus serves as a reservoir for additional water beyond that normally contained within the main float-chamber 10 proper. Since such additional water must also drain away through the syphonic tube- sections 16a, 16b before the water-level in the main chamber 10 drops sufficiently to open the water-inlet valve 2, it will be appreciated that the provision of the supplementary reservoir chamber 20 results in a further delay in the opening of the water-inlet valve 2 as compared with the embodiments of Figures 2 and 3.

That of course could be achieved merely by providing a main float- chamber 10 of increased volume. However, the virtue of the arrangement shown in Figures 4 and 5 lies in the fact that the supplementary reservoir chamber 20 is of channel-section, with slots 22a, 22b and so on (as many as may be thought appropriate) recessed into both sides and the bottom of the channel-section reservoir chamber 20, into one or other of which slots 22 there can be removably inserted a correspondingly-dimensioned adjustment plate 23. The effective additional volume of water contained in the reservoir chamber 20 is thus determined by the placing of the adjustment plate 23 in one of the various slots 22a, 22b and so on. By varying the effective volume of the reservoir chamber 20 (and thereby of the float-chamber as a whole) in this manner one can within certain limits (and by quite small increments) vary the set delay in the opening of the water-inlet valve 20. This facility may therefore be used to "tune" the system for optimum operation, and/or used in other applications.

Referring now to Figure 6, it will be seen that at the apex of the syphonic drainage assembly 16a and 16b for the main float-chamber 10 (which apex is near but appreciably below the maximum water-level C in the cistern 1 ), the non-capilliary chamber 17 is provided with an aperture 30, normally sealed (as shown) by a sealing pad 31 mounted on one end of a rocker arm 32, pivoted at 33 and the other end of which is attached, via a suitable linkage, to an auxiliary float 34 movable vertically within an open- topped auxiliary float-chamber 35. It will be noted that the auxiliary float- chamber 35 is relatively shallow (compared with the depth of the main float- chamber 10) so that is can be located with its bottom 36 at or above the level at which the main float 13 would begin to be displaced by gravity from uppermost position. The open-topped auxiliary float-chamber 35 is moreover located within the cistern 1 with its lip 37 near but appreciably below the maximum water-level C within the cistern 1 defined by the lip 11 of the main float-chamber 10, and at substantially the same sub-surface level as the aperture 30.

When the auxiliary float-chamber 35 is full the auxiliary float 34 is fully submerged and it is both urged by its buoyancy towards and maintained in its upper, enabling position (as shown in full lines in Figure 6) where via rocker arm 32 it forces the pad 31 into sealing engagement with aperture 30. However, the auxiliary float-chamber 35 is provided near its bottom 36 with a small drainage outlet 38. When the cistern is flushed empty and thereafter while it is refilling, water within the auxiliary float-chamber 35 escapes via drainage outlet 38 into the cistern 1 , but so slowly that normally the float- chamber 10 is drained via the syphon 16a, 17, 16b to below the point which will keep the inlet-valve 2 closed before the auxiliary float 34 can be displaced by gravity from its upper, enabling position. It is not precisely important which happens first. The syphon can drain chamber 10 and allow air in the syphon via 16a before the syphon is broken by the auxiliary float dropping or the float-chamber 10 can be drained enough to open the inlet valve before float 34 drops and allows the syphon to be flooded via vent 30 being open or both 16a and 30 allowing air out during filling. This allows aperture 38 to be as large as possible and responsive to a faster slow-leak.

However, when the cistern 1 has been refilled and the water-inlet valve 2 has shut off, if there is a slow-leak from the cistern (for instance if the flushing water-outlet in a gravity-drain system closes but fails to seal the outlet properly) then the water-level in the whole cistern falls but only quite slowly. The water-levels in both the main float-chamber 10 and the auxiliary float-chamber 35 are then able to accommodate themselves quite readily to the falling water-level in the cistern, and more or less coincide with it. Due to the location of the auxiliary float-chamber 35 and its relatively shallow depth it is however the float 34 therewithin which will be first to de-submerge, and then under gravity fall to its lower, disabling position (shown in dotted lines in Figure 5) at which via rocker-arm 32 it lifts the sealing pad 31 from aperture 30. When aperture 30 is thus unsealed, air is admitted therethrough into the apex of the syphonic system 16a, 17 and 16b, thus disabling it and terminating any further discharge of water from the main float-chamber 10 before the main float 13 therein falls sufficiently to open the water-inlet valve. The leakage from the cistern 1 is thus restricted to one cistern-full of water, say about 7 litres, and the wastage is not aggravated by the admission of further water from the mains supply 3 via the water-inlet valve 2.

And when subsequently the slow-leak is cured and the cistern 1 is refilled (by whatever means, but see especially later, with reference to Figures 15-17) the rising water-level within the cistern will also rise up within syphonic tube-section 16b and to the top of non-capillary chamber 17, thus purging the syphonic system 16a, 17 and 16b of air which is driven out through aperture 30 before the water-level in cistern 1 over-tops lip 37 and re-floods auxiliary float-chamber 35, thus returning auxiliary float 34 to its normal, upper enabling position (as shown in full lines) and once more pressing pad 31 into sealing engagement with aperture 30.

The embodiment of Figure 6 as described above will at best function well to restrict the wastage of water by a slow-leak as described above, but suffers from the general liability of things mechanical to malfunction and has a particular weakness in that it is entirely dependent for normal functioning upon the efficiency of the seal between the sealing pad 31 and the aperture 30. It is therefore recommended instead to employ an entirely hydraulic, non-mechanical arrangement to achieve the same purpose of restricting wastage due to a slow-leak, such as that described below.

Referring now to Figure 7, this is in most respects identical to the embodiment of Figure 6, and indeed likewise includes a similarly- dimensioned and located auxiliary chamber 35 - which however does not in this case include a float therein, nor does it have a water-outlet direct to the cistern 1. Instead there is provided a secondary syphonic tube section 40 having its inflow point 41 adjacent the bottom 36 of the auxiliary chamber 35 and its outflow point at the apex of the syphonic system 16a, 17, 16b and 40. Although for clarity shown in Figure 6 as being very similar to the other tube- sections, the tube-section 40 is in fact of narrower bore than tube-sections 16a and 16b, so that when the cistern 1 is flushed the water-level within chamber 35 (as with the embodiment of Figure 6) falls so slowly that the water level in float-chamber 10 is drained away until air enters the syphon section 16a and thus breaks the syphonic path before the water level in chamber 35 drops to allow air into the syphon via inflow point 41.

Thus, on normal flushing the syphonic system 16a, 17, 16b will drain main float-chamber 10 allowing the water-inlet-valve 2 to open after the flush has finished, and then continue draining until air enters the syphon via tube 16a. Some water then falls back down tube 16a, and a partial vacuum then occurs in non-capilliary chamber17 because water seals both tubes 16a and 16b, as well as the other syphonic tube 40. This partial vacuum subsequently drains chamber 35, until air then enters via tube 40 and the syphon is vented. When the cistern refills, water enters via tubes 16a and 40 to purge most of the air from non-capilliary-chamber 17 to ensure that the syphon operates on the next flush cycle.

However, when there is a slow-leak from the cistern the water-level in chamber 35 has time to accommodate itself to the level in the cistern, and falls with it (draining out via syphonic outlet 16b) until chamber 35 becomes empty, thus exposing the inflow point of secondary syphonic tube 40 and admitting air therethrough to the apex of the syphonic system 16a, 17, 16b and 40, thereby disabling the whole syphonic system and shutting off discharge of water from the main float-chamber 10, just as in the embodiment of Figure 6.

A more realistic embodiment, working in the same way as just described above with reference to Figure 7, is depicted in Figures 8 to 10, where as appears from Figure 8 the auxiliary chamber 36 is disposed not to one side of it (as in Figure 7) but within the mouth of the main float-chamber 10 and above the main float 13. Water from the auxiliary chamber 36 again exits therefrom via water-inflow point 41 and syphonic tube 40, which joins the main syphonic system comprising syphonic tubes 16a and 16b at its apical invert point as before - but the syphonic tubes 40 and 16a are arranged side-by-side, as can best be seen from Figures 9 and 10. Despite these constructional differences, the mode of operation of this embodiment is however identical to that already described with reference to Figure 7.

A more elaborate arrangement, to deal not only with slow-leaks but also with fast-leaks, is shown in Figures 11 and 12, where the main float- chamber 10 contains the main float 13, connected by post 14 to the actuating mechanism (shown only schematically) of water-inlet valve 2. As with all the other embodiments, when the float-chamber 10 is full the float 13 is fully submerged and urged by its buoyancy in to its uppermost position (shown in full lines) at which the water-inlet valve 2 is shut off - but when the float- chamber 10 is empty the float 13 normally falls to its lowest position (shown in dotted lines) at which it opens the water-inlet valve 2. As with the embodiment of Figure 6, there is an auxiliary float-chamber 35 containing an auxiliary float 34 which in the case of a slow-leak descends as water escapes through drainage outlet 38 until it coacts with rocker-arm 32 to lift sealing pad 31 from the aperture 30, which in that case disables the discharge of water from the main float-chamber via syphonic system 16a, 17 and 16b, and thus prevents the water-inlet valve 2 from opening and thereby increasing the wastage of water.

However, in order to deal also with a fast-leak, in the embodiment of Figures 11 and 12 the rocker-arm 32 is additionally provided beyond the sealing pad 31 with a two-pronged, bifurcated extension lever 50. The respective prongs 50 surround the post 14, one on either side of it, but do not normally engage with it in any way, neither when the main float-chamber 10 is full nor when it is empty. However, the end of rocker-arm 32 remote from the two-pronged lever 50 is connected to the auxiliary float 34 within auxiliary float-chamber 35. As already described, in the case of a slow-leak from the cistern, the escape of water from auxiliary float-chamber 35 through drainage outlet 38 will ultimately lower the float 34 to its disabling position (shown in dotted lines) and via rocker-arm 32 lift the sealing pad from the aperture and prevent the water-inlet valve from opening. In the case of a fast-leak the water-inlet valve will however have already opened - and is prevented by the fast-leak from being re-closed in the normal manner by the rising water-level in the cistern over-topping and flooding the main float-chamber 10.

The auxiliary float-chamber 35 is however also provided with a supplementary drainage outlet 51 , adjacent its bottom 36, through which water continues to escape (albeit slowly) allowing the auxiliary float 34 to descend still further, and thereby rotating rocker-arm 32 from its normal angular attitude α first to an intermediate angular attitude β and ultimately to its final angular attitude γ.

The post 14 is additionally provided with suitably-located, oppositely- extending lateral projections 52 - with which the respective prongs of the bifurcated lever 50 rise into engagement when the rocker-arm 32 reaches its intermediate angular attitude β. Further descent of the auxiliary float 34 then rotates the rocker-arm 32 from angular attitude β to its final angular attitude γ, and as it rotates the prongs of bifurcated lever 50 engage the lateral projections 52 thereby lifting the post 14 (and indeed also the main float 13) upwards and thus close the water-inlet valve 2, bringing the fast-leak to an end.

The mechanical arrangement for dealing with a fast-leak just described with reference to Figures 11 to 12 is however again open to the possibility of malfunction, and accordingly it may with advantage be replaced by an hydraulic alternative, as will now be described.

Referring to both the embodiments of Figures 13 and 14, much as before (see Figure 6) the cistern 1 is equipped with a water-inlet valve 2 connected to the mains-water supply 3. The inlet-valve 2 (shown in its closed position) is actuated via stub-arm 5 and pivotally-mounted lever 7 by post 14 secured to float 13 within main float-chamber 10.

In normal operation when the cistern is flushed water escapes from the main float-chamber 10 via the exit near its bottom and through the syphonic system 16a, 16b, but it escapes in this way only slowly, thus delaying the descent of the float 13 (and consequent opening of the inlet- valve 2) until after the cistern-flushing valve (not shown here - but see Figure 15) has closed. The cistern 1 then refills fairly quickly, and when the water therein reaches the desired level C it over-tops lip 11 and floods float- chamber 10, thus more or less instantaneously raising float 13 to its uppermost position and through post 14, pivotally-mounted lever 7 and stub- arm 5 closing the inlet-valve 2. In the case of a slow-leak, such as when the cistern-flushing valve closes but does not seal properly, the cistern refills to level C and shuts off the water-inlet-valve 2, but thereafter the level of water in the cistern slowly falls again. This would ultimately result in the inlet-valve 2 re-opening were it not for the alternative further arrangement described below.

Referring first to Figure 13 (which otherwise corresponds to Figure 6) within the mouth of the main float-chamber 10 there is arranged an annular plug 55 of an open-pored, porous material, having a vertical and axial passageway 56 therein through which passes the post 14 that interconnects the main float 13 with the pivotally-mounted lever 7. When on refilling the cistern to level C the water over-tops the lip 11 it still floods the float-chamber

10 via passageway 56 but also saturates the porous plug 55. When the cistern is flushed, the float-chamber 10 is as before emptied via the syphonic systems 16a, 17 and 16b, and then the syphon is broken. When however there is a fast-leak from the cistern, it does not refill to level C to over-top lip

11 and re-flood the main float-chamber 10, but instead water slowly drains out of the porous plug 55 and (because it is no longer extracted there from by the syphonic system) in due course refills float-chamber 10 sufficiently to raise the float 13 and thereby shut-off the cistern water-inlet-valve 2.

In the alternative embodiment of Figure 14 (which otherwise corresponds to Figure 7) within the mouth of the main float-chamber 10 there is arranged an annular auxiliary chamber 39, surrounding the post 14 which interconnects the float 13 and the pivotally-mounted lever 7. Water within the auxiliary chamber 39 can escape through the drainage outlet 42 into the float-chamber 10. In normal operation this happens so slowly that auxiliary chamber 39 never has time to empty before it is overtopped and re-flooded as the cistern refills. When however there is a fast-leak, auxiliary chamber 39 empties slowly via aperture 42 into the empty chamber 10 thereby raising the float 13 to close the inlet valve 2. The leakage rate via aperture 42 is arranged so that sufficient water is added to chamber 10, which will affect the float 13, only after a period of time which is outside the normal flush cycle.

The embodiments of valve-actuator mechanism as described above are highly effective in achieving the most basic objectives of this invention of avoiding or minimising water-wastage (to the extent possible with any particular arrangement) not only by delaying opening of the water-inlet valve in normal operation, but also by preventing its opening in the case of a slow- leak and re-closing it in the case of a fast-leak. In the case of either of the just-mentioned malfunctions, one is however left with an empty cistern and a closed water-inlet valve - so it is then desirable for it to be able, under external, manual control, to reset the whole arrangement by refilling the cistern for normal operation. This can be neatly achieved via a modification of the conventional cistern-flushing mechanism of the bottom-opening, gravity-drain type, as will now be described.

Referring now to Figures 15 - 17, the overall arrangement comprises the cistern 1 , with mains-water-iniet-valve 2 connected to the mains-supply 3. The cistern is of the bottom-opening, gravity-drain type, in which the flushing mechanism is generally indicated 8, and essentially comprises a large-bore water-outlet 60 through which all the water within the cistern can be quickly 'dumped' in the direction of arrow E into a lavatory pan (not shown) so as to flush it clean. Except when the cistern is flushed, the water-outlet 60 is however blocked by an inverted-mushroom-shaped buoyant float-plug 61 , normally held in situ (despite its natural buoyancy) by the pressure of the water within the cistern, as shown in full lines in Figure 15.

The float-plug 61 is arranged at the bottom of a stem 62, by means of which it may be manually lifted against water-pressure and gravity out of sealing engagement with the water-outlet 60, so as thus to flush the cistern. Once the outlet has been thus un-blocked, the buoyancy of float-plug 61 supports it at or adjacent its upper position (shown in dotted lines) within an housing-cage 63 until the cistern 1 has effectively emptied, when the water therein falls to level D, and the float-plug under gravity re-seats itself in the water-outlet 60, thus making the cistern 1 ready to be refilled.

At or about this point in time, the valve-actuator mechanism (which at its left-hand side is identical to the embodiment of Figure 8) in normal operation allows the float 13 to descend from its uppermost position (as shown) to its lowermost position (shown in full lines) thus opening water-inlet 2 to refill the cistern 1 from the mains-supply 3. If however the float-plug 61 fails to seat itself properly in the water-outlet 60 there will be a slow-leak which gradually empties the cistern 1 again, after it has been refilled and the water-inlet has shut off. In that event, as in the embodiment of Figure 8, the gradual reduction in water-level within the auxiliary chamber 35 will disable the syphonic system 40 before the float 13 is de-submerged in main float- chamber 10, thus cutting off discharge of water therefrom via syphonic system 16b, and thereby preventing water-inlet-valve 2 from opening.

That in itself is as intended, but one is left with an empty cistern and the water-inlet shut off, so it is desirable to be able to over-ride the water- inlet shut-off arrangement, but of course without opening the water-outlet from the cistern.

In order to over-ride the water-inlet shut-off arrangement, it will be seen that the upper part of stem 62 is provided with an annular flange 64, and the main float-chamber 10 is extended to accommodate a displacement member 65. In normal operation displacement member 65 occupies its lowermost position (as shown) and has no effect upon the level of water within the float-chamber 10. The member 65 is however provided with an upstanding pillar 66 carrying two horizontally-directed arms 67 which pass one each side of stem 62, and when the latter is lifted sufficiently the arms 67 will be engaged by annular flange 64 and then raised by it to the topmost position shown in dotted lines in Figure 14. As the arms 67 and pillar 66 are raised, so too is the displacement member 65 - which then no longer occupies so much of float-chamber 10, and its removal causes the water- level within the latter to fall to such an extent that the float 13 descends to its lowermost position (shown in dotted lines) and thereby opens the mains- water-inlet-valve to refill the cistern 1.

The stem 62, annular flange 64, parallel arms 67, pillar 66 and displacement member 65 must however all be held in their uppermost position while the cistern 1 refills, and of course the cistern will not refill if lifting stem 62 has raised the float-plug 61 and thus opened the water-outlet 60. It is therefore necessary to disable the normal outlet-opening operation of the stem 62 when it is desired to reset the water-inlet mechanism.

For that purpose the stem 62 is constructed with coaxial upper and lower sections, respectively 62a and 62b. When the cistern 1 is more or less full, these are interconnected for conjoint vertical movement (as when flushing the cistern) by a buoyancy-actuated latch-member 68, pivotally- mounted at or adjacent the top end of lower stem section 62b and which engages (as shown in Figure 16), with a detent 69 provided at or adjacent the bottom end of upper stem sections 62a. When however the cistern 1 is more or less empty, the pivoted latch-member 68 is no longer supported by its buoyancy, and its weight causes it to pivot and thereby detach the latch from detent 69. In this condition the upper stem section 62a can therefore be lifted, thereby raising the displacement member 65 and thus opening the water-inlet 2, without raising the float-plug 61 and thereby opening the water- outlet 60.

As previously mentioned herein, in certain circumstances instead of shutting down the lavatory flush system (until it has been repaired) in response to a slow-leak (or even perhaps a fast-leak) it may be better simply to signal the existence of such a leak while leaving the lavatory flush system still operational.

Such an alternative embodiment of the invention, which incorporates a leak-alert device, is illustrated in Figures 18 and 19. The lower (leaking) water level F in the cistern is indicated by locating a separate cup 70 in the cistern with its open top just below the high water level C. A float-actuated bellows 72 is positioned in the cup 70, with one end of the bellows 72 sealing to, and fixed to, the base of the cup 70 and the other end of the bellows attached to a weighted float 71. When the cup 70 is full of water the float 71 opens the bellows 72 creating a partial vacuum in the bellows 72. When the water level in the cup drops to level F, the float 71 sinks thus closing the bellows 72 to create a slight over-pressure therein.

As best seen in Figures 20 and 21 , a capillary tube 74 from the bellows leads to an indicator 75 which contains a membrane 76a which is deflected by the change in pressure. The movement of the membrane, by this change in pressure from positive to negative or vice versa, can be used to cover or expose a symbol showing whether the cistern is leaking or not. In order to avoid the indicator operating during a normal flush the cup 70 containing the float 71 and bellows 72 has a small outlet 73 near the base of the cup leaking the contents of the cup into the cistern. The outlet 73 is arranged to drain the cup 70 to the level where the float 71 will begin to collapse the bellows 72 only after a period of time outside a normal flush cycle.

The cistern will therefore empty and refill before the float 71 moves the bellows 72 to affect the indicator 75 during normal operation.

The indicator 75 can be located anywhere outside the cistern. The capillary tube 74 can be led out via the cistern vent aperture. It is possible to locate the indicator within or close to the flush operating handle or knob.

Figures 22 and 23 show another embodiment of the invention. This in general is similar in function to Figures 18 and 19, but in this embodiment a reed switch is incorporated in the base of the cup 75 with the connecting leads 79 from the reed switch 78 connected to an indicator 80 which can be visual, audio or can be a transmitter for remote indication (battery-power supply for the indicator has been omitted for clarity). Inserted in the base of the float 76 is a magnet 77. When the cistern is full to level C the float 76 and magnet 77 do not affect the reed switch, and the reed switch contacts remain open. When however the cistern leaks, the water level drops to the lower level F, whereupon the float 75 and magnet 76 drop, causing the reed switch contacts to close and thereby signalling a leaking condition at indicator 80. Retaining tangs 81 at the top of the cup ensure that the float 76 stays within the cup 75. As in Figure 19, the leakage aperture 73 prevents a leak being indicated during normal operation.

Alternatively, an external magnetic indicator, similar broadly-speaking to a magnetic compass, can also be used to sense the location of the internal magnetic float and thus to indicate a leaking condition at level F.

Another possibility is for the delay mechanism to be electronic, whereby the indicator is only switched on after a period of time outside a normal flush cycle, if it has not previously been switched off by the rising water level during a normal cistern refill.

It is also possible to use a float-actuated level switch to directly sense that the water level has dropped to level F or lower, and to use the electronic delay-mechanism described above to prevent the indicator being switched on during normal operation.

These arrangements as just described above are directed to sensing and signalling a slow-leak, in which the leakage rate is less than the rate of supply via the inlet valve. However it will of course be readily appreciated that, mutatis mutandis, a fast-leak could also be shown by these indicators.

Referring now to Figure 24, this shows a gravity base-outlet valve flush mechanism akin to that of Figure 15, having a float-plug 61 arranged at the bottom of a stem the top end of which is indicated 62a. The outlet valve lifting stem 62a is however provided with an extension 93, and connected to this extension is a permanent magnet 91. Inside the float cup 10 is a magnetically attracted float 90, positioned above the inlet valve operating float 13. Preventing float 90 from rising out of the float cup is a spoked guide tube 92, the spokes attached inside the top rim of the float cup positioning the guide tube centrally in the float cup, but still allowing the cistern water to freely enter the float cup when the water level overtops the cup rim. The magnetically attracted float 90 has a buoyancy which just allows it to float, this is in order to maximise its active weight. When the cistern is full the float 90 is positioned at the top of the float cup, as shown, due to its own buoyancy and also due to the magnetic attraction with magnet 91. When the cistern is flushed stem 62a is raised, and this also raises the magnet 91 disconnecting it from float 90, until stem 62a returns to its former position. Because the duration between the raising and falling of rod 62a is short (the outlet valve 61 returns to its closed position independently of the lifting mechanism as the cistern water level drops) the magnet 91 is usually reconnected with the float 90 before the float cup 10 is significantly drained by the syphon. If the flush mechanism is purposely held open for a longer period the float 90 will drop with the falling water level in the float cup and rest on the float 13 until the cistern refills, which will then raise float 90 to reconnect with magnet 91 ready for the next flush. If the cistern outlet valve develops a leak, the cistern will empty leaving the inlet valve closed, because cup 10 will have sufficient water to keep float 13 fully raised. Float 90 will remain at the top of the float cup due to the attraction of magnet 91. The next time the cistern is operated, magnet 91 will be lifted away from float 90 allowing float 90 to drop onto float 13 adding sufficient weight to reopen the inlet valve to refill the cistern. The fact that the cistern has to refill before it can be flushed should give a clear indication that the outlet valve is leaking and should be replaced. The connection between the flush mechanism and the magnet 91 (which is represented by extension 93 in the diagram) can take many forms to suit the particular flush mechanism. The interconnection method shown in subsequently described Figure 25 (represented by overlapping discs 103 and 104) could also be adopted to lift magnet 91 sufficiently when the flush mechanism is raised to its full extent. Referring now to Figure 25, this again shows a gravity base-outlet valve-flush mechanism including float-plug 61 , outlet-valve lifting stem 62a, 62b and cage 63. The outlet-valve lifting stem 62a is however provided with a fixed disk 104. The float cup 10 is provided with aperture 100 in its base. A guided vertical rod 102 is positioned within the cup 10 directly above aperture 100. Fixed to the lower end of rod 102 is a sealing member 101 which seals aperture 100. Fixed to the upper end of rod 102 is disk 103. The relative diameters of disk 103 and disk 104 are arranged such that they overlap each other to provide an interconnection between the flush mechanism and the opening and closing of aperture 100. The disks 103 and 104 could be simple extensions from rod 102 and stem 62a if required, but disks avoid orientating simple extensions, and allow free rotation of the components involved. When the flush mechanism is raised to its full extent, disk 104 contacts disk 103, lifting rod 102 and seal 101 away from aperture 100, as shown by broken line outlines in the diagram. When the flush operating mechanism is released it drops, as then so too does seal 101 to close aperture 100. If the outlet valve develops a leak, the inlet valve will remain closed due to the water level remaining in cup 10. The empty cistern can then be refilled by raising the flush mechanism fully for a short period (say 10 seconds) which will drain the float cup 10 sufficiently to allow float 13 to drop, causing the inlet valve to re-open. A necessary requirement is that aperture 100 is closed effectively by seal 101 , during the period when the cistern is refilling, or when the cistern is empty due to a leaky outlet valve. This can be accomplished by competent design. However, reliability and durability may be enhanced by increasing the bouyancy of rod 102, so that it increases the sealing force on aperture 100 when the float cup 10 is empty or partially empty, but reduces the sealing force when cup 10 (and the cistern) is full. Therefore, for the longer period which is generally when the cistern is full, and when there is no requirement for aperture 100 to be sealed, the sealing force can be beneficially reduced. In overall summary, it will be seen that the present invention provides a delayed-action float-operated cistern water-inlet valve-actuator system which , when installed in a WC toilet cistern, ensures that fresh water cannot be added until after the flush has been completed. Especially the preferred embodiments of the valve-actuator system here disclosed have many advantages, thus for instance:

- as much as 10% of the flush volume (say up to one litre of water) can often be saved at each flush;

- the submerged float enables the design of the float and float-arm to be smaller and more compact;

- the fully-submerged float also eliminates scale build-up thereon, which can increase the weight of the float and consequently raise the water level, and thereby should give improved reliability in hard-water areas;

- the syphon system is automatically primed each time the cistern is filled, and is fully reliable;

- the water level is accurately controlled, and the valve has a positive closure;

- there is improved isolation between the fresh water entering and the soil water leaving the cistern;

- with minimal cost, existing cisterns can be upgraded so as to reduce water-consumption and improve operation;

- no modifications are required to existing types of cistern;

- there are no additional valves, and there need be no additional moving parts; and

- there can be an improved flush flow, due to reduced turbulence.

Claims

1. A valve-actuator for use in conjunction with a lavatory-flush cistern to enable and control its refilling via a cistern water-inlet valve from a water- supply, which valve-actuator comprises:

- a main float-chamber able to communicate freely with the cistern at or closely adjacent to and below the desired maximum water-level therein and which therefore is over-topped and floods when the cistern fills to that level;

- an attachment point associated with the float for operating means responsive to its position within said main float-chamber which operating means are adapted either directly or indirectly to close the cistern water-inlet valve when the float is in its uppermost position and conversely to open said cistern water-inlet valve when the float is in a lower position; and

- a main float-chamber drainage outlet through which, when the water- level in the cistern falls as the lavatory is flushed, the water within said float- chamber is discharged at a controlled rate such that the float does not de- submerge and then fall from its uppermost position, thereby opening the water-inlet valve and commencing to refill the cistern, until flushing has effectively-emptied the cistern, thus obviating water-wastage.

2. A valve-actuator as claimed in claim in claim 1 , in which the uppermost position of the float is one at which it is fully or substantially fully submerged when the float-chamber is flooded.

3. A valve-actuator as claimed in claim 1 or claim 2, in conjunction with a water-inlet-valve for the cistern of the equilibrium type.

4. A valve-actuator as claimed in any of the preceding claims, in which the main float-chamber is an open-topped cup for location within the cistern so that the lip of that cup substantially defines the desired maximum water-level in the cistern.

5. A valve-actuator as claimed in any of the preceding claims, in which the operating means comprise one or more linkage(s) secured to said attachment point and which are operative while the float is at its uppermost point to close a cistern water-inlet valve from a water-supply.

6. A valve-actuator as claimed in any of the preceding claims, in which the float-chamber drainage-outlet is a syphonic-tube with its inflow end connected to said float-chamber at or adjacent the base thereof and below the lowermost point of the float therein, said tube having its apex and invert point closely adjacent to but just below the level of communication between the float-chamber and the cistern, and its outflow end disposed below its inflow end.

7. A valve-actuator as claimed in any of the preceding claims, which also includes:

- a water-inflow restrictor associated with said drainage-outlet which is adapted, as the water-level in the cistern rises on refilling same, to restrict or prevent refilling of the main float-chamber by back-flow via said drainage outlet, to such an extent that said float-chamber is sufficiently filled to move the float to its uppermost closed position, and thus close the cistern water- inlet valve, only when the water in the cistern reaches its desired maximum level and thereby over-tops and floods the main float-chamber.

8. A valve-actuator as claimed in claim 6 and claim 7, in which the water- inflow restrictor against back-flow through the drainage-outlet comprises a non-capillary chamber interposed in the syphonic tube between its apex and its end that communicates with the cistern.

9. A valve-actuator as claimed in any of the preceding claims, which also is further provided with an open-topped reservoir chamber which communicates with the main float-chamber and has its lip at the same level as the lip thereof, said reservoir chamber being of adjustable magnitude, so as to vary the effective volume of said reservoir chamber and thereby of that part of the main float-chamber as a whole which is above the natural buoyancy level of the float when the latter is in its uppermost position, thus enabling the delay imparted to the opening of the water-inlet valve to be varied within limits.

10. A valve-actuator as claimed in claim 9, in which the variable-volume reservoir chamber is or includes an extension of generally channel-section provided with a series of spaced slots recessed into the sides and bottom of said channel-section reservoir and a correspondingly-dimensioned sealing plate for insertion at will into one or other of said spaced slots so as incrementally to vary said effective volume.

11. A valve-actuator as claimed in any of the preceding claims, which also includes additional means responsive to a slow-leak from the cistern to disable the discharge from the float-chamber of the water which is above the natural buoyancy level of the float when the latter is in its uppermost position, and thereby prevent opening of the water-inlet valve.

12. A valve-actuator as claimed in any of claims 6, 7 and 11 , in which the disabling means comprise:

- an auxiliary float-chamber able to communicate freely with the cistern at a level closely adjacent to but just below its desired maximum water-level;

- an auxiliary float within said auxiliary float-chamber and movable therein under gravity between an upper enabling position and a lower disabling position, and vice versa under buoyancy, the auxiliary float when as normal the auxiliary float-chamber is full being submerged below its natural buoyancy level and therefore positively urged towards its upper enabling position but when the auxiliary chamber is emptied urged by gravity towards its lower, disabling position;

- an aperture in and substantially at the apex of the syphonic tube through which water is discharged from the main float-chamber, and a valve member which normally seals said aperture;

- one or more mechanical interconnection(s) between the valve member and the auxiliary float so arranged that when the auxiliary float falls under gravity to its lower, disabling position the valve member is caused to unseal the aperture, thus breaking the syphonic path and disabling further discharge of water from the main float-chamber; and

13. A valve-actuator as claimed in claim 12, in which the mechanical interconnection(s) comprise a pivotally-mounted arm connected at one side of the pivotal connection to the auxiliary float and on the other side thereof provided with a sealing pad which normally bears down upon and thus seals the aperture in the apex of the syphonic tube.

14. A valve-actuator as claimed in any of claims 6, 7 and 11 , in which the disabling means comprise:

- a second syphonic tube running from a point at or closely adjacent to the bottom of said auxiliary chamber to join the first syphonic tube at or closely adjacent its apex, so that whenever the said auxiliary chamber becomes empty air will enter the syphonic system via the second syphonic tube to disable the discharge of water from the main float-chamber via the first syphonic tube; - said second syphonic tube being however so dimensioned relative to the first syphonic tube that water escapes from the auxiliary chamber via the syphonic system so slowly that on normal flushing of the cistern the first syphonic tube will drain the main float-chamber and allow air to enter the syphon via the first syphonic tube before the second syphonic tube can drain the auxiliary chamber.

15. A valve-actuator as claimed in claim 6 or any claim dependent thereon, in which the float-chamber is provided with an additional magnetically- attractive just-buoyant float disposed therein above the float proper, and externally of said float-chamber a magnet vertically moveable by the flush mechanism, said magnet serving to retain the magnetically-attractive additional float inoperative at the top of the float chamber save when the flush-mechanism is actuated and thereby breaks the magnetic attraction therebetween.

16. A valve-actuator as claimed in any of the preceding claims, which includes means responsive to a fast-leak from the cistern to over-ride the normal water-inlet valve-control mechanism and bring about closure thereof even though the main float-chamber has not been over-topped and flooded.

17. A valve-actuator as claimed in claim 16, in which the over-ride means comprise an auxiliary float-chamber, an auxiliary float within said auxiliary float-chamber movable between an upper inoperative position and a lower operative position, a pivotally-mounted lever one end of which is movable responsive to movement of the auxiliary float within the auxiliary float- chamber, the other end of said pivotally-mounted lever being normally disengaged from the main float and associated valve-operative linkage(s) but engagable therewith as the auxiliary float approaches its operative position and when thus engaged able to lift said linkage(s) towards and into the water-inlet valve-closing position as said auxiliary float falls to its fully- operative position, as well as one or more slow-drain outlet(s) from said auxiliary float-chamber so dimensioned that when there is no fast-leak from the cistern which therefore refills at a desired rate the auxiliary float-chamber will flood, thus restoring the lever to its inoperative position, before the auxiliary float has fallen to its operative position.

18. A valve-actuator as claimed in claim 13 and in claim 16, in which an extension of the pivotally-mounted arm provided with the sealing pad to disable a slow-leak serves also as the lever engagable with the main float and its associated linkage(s) to shut off the water-inlet valve in the case of a fast-leak.

19. A valve-actuator as claimed in claim 16, in which the over-ride means responsive to a fast-leak comprise an open-pored porous slow-release sponge-type material disposed within the main float-chamber above the uppermost position of the main-float therein, from which sponge-type material, when the water-level in said float-chamber has fallen to open the cistern water-inlet-valve, sufficient water will be released so as once more to raise the water-level in said float-chamber and thereby re-close the cistern water-inlet valve, but only over a period outside the normal filling time of the cistern.

20. A valve-actuator as claimed in claim 16, in which the over-ride means responsive to a fast-leak comprise an open-topped chamber which communicates with the main float-chamber above the uppermost position of the main float therein via a small-leakage aperture though which, when the water-level in said float-chamber has fallen to open the cistern water-inlet valve, water will enter the float-chamber so as once more to raise the water- level therein and thereby re-close the cistern water-inlet valve, but only over a period outside the normal filling time of the cistern.

21. A lavatory-flush cistern, fitted with a water-inlet valve for connection to a water-supply and with a flush mechanism, in which the water-inlet valve is provided with a delayed-action valve-actuator as claimed in any of the preceding claims.

22. A lavatory-flush cistern as claimed in claim 21 , in which the water-inlet valve is of the equilibrium type.

23. A lavatory-flush cistern as claimed in claim 21 or claim 22, in which the flush-mechanism is of the bottom-opening, gravity-drain type.

24. A flush-mechanism of the bottom-opening gravity-drain type, for use in a lavatory-flush cistern as claimed in claim 23, which flush-mechanism comprises:

- the engagement/disengagement of the catch member with the abutment being controlled by a float member responsive to the presence or absence of water within the cistern, so that when the water in the cistern is above a predetermined point level the catch member engages with the abutment but disengages therefrom when the water-level falls to a lower level; and

- means operable by lifting the upper section of the plunger when it is disengaged from the lower section thereof to over-ride the valve-actuator when it has shut off the cistern water-inlet valve so as to re-set the system for normal operation.

25. A flush-mechanism as claimed in claim 24, in which the means for overriding the water-inlet valve-actuator comprise a displacement member which normally restricts the effective volume of the main float-chamber of said valve-actuator but which on lifting the upper section of said plunger, when disengaged from its lower section, is raised thereby increasing the effective volume of said float-chamber and therefore reducing the water-level therein thus opening the cistern water-inlet valve.

26. A flush-mechanism as claimed in claim 24 or claim 25, in which the bottom of the float chamber is provided with a drainage outlet normally closed by a seal moveable in and out of sealing engagement with said outlet by a rod actuable to break said seal when the flushing mechanism is operated.

27. A lavatory-flush cistern as claimed in any of claims 21 to 23 which incorporates a flush-mechanism as claimed in either of claims 25 or 26.

28. A leak-alert device comprising in combination a delayed-opening cistern water-inlet valve as claimed in any of claims 1 to 8, especially for use in conjunction with a bottom-opening, gravity-drain cistern, together with a sensor/signal device able to sense the establishment of a valve-open/close water-level within the cistern and then, responsive thereto, to signal the existence of a leak from the cistern water-outlet valve.

29. A leak-alert device as claimed in claim 28, in which the sensor/signal device is one able to sense the establishment of the valve-open/close water- level in situ within the cistern but to transmit a signal indicative of that state and thus the existence of a slow-leak to a remote indicator.